The Lindblad coefficients (volatilities) \(\xi _{0,j}\)  specify the strength of the white noise. We may assume that the interaction of the 3-level system of the electronic ground state of the NV center with the environment is equivalent to the interaction of the NV spin with magnetic noise arising from a spin bath or several spin baths. The Lindblad operators for this case can be taken to be the three spin-1 operators, \({\cal V}_j = S_j\)  (\(S_x, S_y, S_z\)  for \(j =x, y, z\) ). A NV near the diamond surface experiences a bath due to noise originating from the diamond surface that has fast correlation times, perhaps even as fast as \(\tau _c \approx 10^{-11}\)  s  [1]}. Therefore, shallow NVs in diamond have an environment correlation time comparable to, or shorter than, the energy splitting parameter \({\cal D}^{-1}\) , and one approaches the white noise limit.
Hence, shallow NVs can be modeled by the Lindblad master equation (REF ) [2]}. Note that experimental NV coherence times reported in Ref. [1]} are on the order of tens to hundreds of \(\mu \) s.
